Japanese advertising giant Dentsu has agreed to acquire Aegis Media in a deal that values the British media buying company at US$4.9 billion.
The shock announcement will create one of the largest media buying groups in Asia Pacific, and give an aggressive Dentsu strong a presence in Europe and North America.
Tadashi Ishii, president and CEO of Dentsu, said the combined companies will deliver best-in-class services to clients through a new global communication network born in the digital age.
"Dentsu and Aegis will be the market leader in the Asia Pacific region, enjoying a strong presence across Europe and the fastest growing agency network in the US," he said.
Under the deal Aegis' biggest shareholder Vincent Bollore agreed to sell a 15% stake to Dentsu and a further 5% soon.
Harold Mitchell, executive chairman of Aegis Media Australia, will retain his seat on the Aegis board. Aegis Media acquired Mitchell Communication Group in July 2010 for A$363 million.
Aegis CEO Jerry Buhlmann said the company was delighted at the prospect of being able to play a full part in "helping Dentsu create a platform for global growth and continued digital innovation."
"By forming the first communications group with true global reach, the growth strategies of both businesses will be enhanced as we provide more scale, geography, capability and investment to support clients," he said.
"We have complementary geographic fits and aligned visions and strategies. Together, we have strengthened investment capabilities as we work to help more clients than ever before navigate the complex and converging media ecosystem."